Bartenders around the world are always on the look-out for new ways to add creativity to their cocktails and they often find inspiration in fields outside their own. No wonder then that one of the biggest trends of this year comes from the wine and whisky industry. This aged-cocktail phenomenon originated in London in 2004 when 69 Colebrooke Row’s bartender Tony Conigliaro, amazed by the taste of a 1920’s bottle of Dubonnet, decided to age cocktails in glass bottles. His work inspired Jeffrey Morgenthaler, a Portland bartender who in turn tried his hands on barrel-aged cocktails, starting the whole trend in 2010. The idea itself isn’t actually new, as two ads from 1910 and 1912 already mentioned aged cocktails.

So, why are aged cocktails that popular? To understand what makes them so special, let’s take a look at what happens during the process. In the case of barrel-aged cocktails, the drink will go through three main stages. First is infusion: the beverage will pick the flavors from the wood itself (usually oak), as well as the remaining flavors of the alcohols (whisky, sherry) previously aged in this particular barrel. Then the air inside the barrel will cause oxidation, which will add nutty flavors to the drink. The last step is extraction, a reaction between the wood and the acidity of the cocktail resulting in sugars that will mellow the beverage. The final product has a smooth and slightly oaky taste mixed with aromas of caramel and vanilla and spicy notes.

Despite their popularity, aged cocktails have drawn a few criticisms from specialists and mixologists. Their first concern is that barrel-aging takes away the floral notes of the drink, removing its most fragrant part. Which goes against the very idea of the cocktail. Then, there is little control over the results, especially in barrel-aging where the wood flavor can easily turn out too powerful. The last point is that since it is a trend, many people jump into it for the sake of it, without clearly knowing what they are doing.

For now, the bottle-aged and barrel-aged cocktail trend seems to please both the customers and the bartenders. The former enjoy the deep flavors of such drinks as well as the novelty effect and the latter are able to serve the patrons much quicker while making more substantial profits.